L. Piron A. Kirk Y. Q. Liu G. Cunningham M. Carr G. Fishpool R. Gowland I. Katramados D. Luckin R. Martin
In magnetic fusion devices, unwanted non-axisymmetric magnetic eld perturbations, known as error fields (EF), can have detrimental effects on plasma stability and confinement. To minimize their impact on plasma performances and on the available operational space, it is important to identify the EF sources and develop EF control strategies. MAST Up…
Preprint PurchaseB. J. Ding P. T. Bonoli A. Tuccillo M. Goniche K. Kirov M. Li Y. Li R. Cesario Y. Peysson A. Ekedahl L. Amicucci S. Baek I. Faust R. Parker S. Shiraiwa G. M. Wallace A. Cardinali C. Castaldo S. Ceccuzzi J. Mailloux F. Napoli F. Liu B. Wan JET Contributors
Progress in understanding lower hybrid current drive (LHCD) at high density has been made through experiments and modeling, which is encouraging given the need for an efficient off-axis current profile control technique in burning plasma. By reducing the wall recycling of neutrals, the edge temperature is increased and the effect of parametric inst…
Preprint PublishedK. G. McClements K. Tani R. J. Akers Y. Q. Liu K. Shinohara H. Tsutsui S. Tsuji-Iio
The application of non-axisymmetric resonant magnetic perturbations (RMPs) to low current plasmas in the Mega Amp Spherical Tokamak (MAST) was found to be correlated with substantial drops in neutron production, suggesting a significant degradation of fast ion confinement. The effects of such perturbations on fast ions in MAST have been modelled us…
Preprint PublishedD. A. Ryan Y. Q. Liu A. Kirk W. Suttrop B. Dudson M. Dunne M. Willensdorfer the ASDEX-Upgrade team and the EUROfusion MST1 team
It has been previously demonstrated in (Li et al 2016 Nuclear Fusion 56 126007) that the optimum upper/lower coil phase shift ΔΦopt for alignment of RMP coils for ELM mitigation depends sensitively on q95, and other equilibrium plasma parameters. Therefore, ΔΦopt is expected to vary widely during the current ramp …
Preprint PublishedX. Yi K. Arakawa D. Nguyen-Manh F. Ferroni P. Liu W. Han F. Wan S. G. Roberts
Helium bubble production in tungsten has been studied combining transmission electron microscopy and in situ irradiations with 10 keV He+ ions. The irradiations were carried out at four temperatures (773 K, 1073 K, 1273 K, 1473 K), and were held at intervals of (0.45; 0.9; 1.2; 1.5) × 1020 He+/m2 for each temperature. Based on detailed analyses of…
Preprint PublishedK. Tani K. Shinohara T. Oikawa H. Tsutsui K.G. McClements R.J. Akers Y.Q. Liu M. Suzuki S. Ide Y. Kusama S. Tsuji-Iio
A non-steady-state orbit-following Monte-Carlo code has been developed. As part of the verification and validation of the code, calculations of time dependent neutron rates have been made for a specific shot in the Mega Amp Spherical Tokamak (MAST) using three-dimensional fields representing vacuum resonant magnetic perturbations (RMPs) and toroida…
Preprint PublishedY. Liu C.J. Ham A. Kirk L. Li A. Loarte D.A. Ryan Y. Sun W. Suttrop X. Yang L. Zhou
Resonant magnetic perturbations (RMP) have extensively been demonstrated as a plausible technique for mitigating or suppressing large edge localized modes (ELMs). Associated with this is a substantial amount of theory and modelling efforts during recent years. Various models describing the plasma response to the RMP fields have been proposed in the…
Preprint PublishedY. Liu S.A. Sabbagh I.T. Chapman S. Gerasimov Y. Gribov T.C. Hender V. Igochine M. Maraschek G. Matsunag M. Okabayashi E.J. Strait
The high-frequency noise measured by magnetic sensors, at levels above the typical frequency of resistive wall modes, is analyzed across a range of present tokamak devices including DIII-D, JET, MAST, ASDEX Upgrade, JT-60U, and NSTX. A high-pass filter enables identification of the noise component with Gaussian-like statistics that shares certain c…
Preprint PurchaseL. Xue X. R. Duan G. Y. Zheng Y. Q. Liu Y. D. Pan S. L. Yan V. N. Dokuka V. E. Lukash R. R. Khayrutdinov
Cold and hot vertical displacement events (VDEs) are frequently related to the disruption of vertically-elongated tokamaks. The weak poloidal magnetic field around the null-points of a snowflake divertor configuration may influence the vertical displacement process. In this paper, the major disruption with a cold VDE and the vertical disruption in …
PublishedY. Liu D. Ryan A. Kirk L. Li W. Suttrop M. Dunne R. Fischer J.C. Fuchs B. Kurzan P. Piovesan M. Willensdorfer The ASDEX Upgrade team The EUROfusion MST1 team
The plasma response to the vacuum resonant magnetic perturbation (RMP) fields, produced by the ELM control coils in ASDEX Upgrade experiments, is computationally modelled using the MARS-F/K codes [Liu Y.Q. et al 2000 Phys. Plasmas 7 3681; Liu Y.Q. et al 2008 Phys. Plasmas 15 112503]. A systematic investigation is carried out, considering various pl…
Preprint Published